Drug-Dispensing Contact Lens Eases Glaucoma Symptoms
Glaucoma is a leading cause of irreversible blindness in the world. A condition of the eye where blocked drainage canals lead to a buildup of pressure and loss of vision, glaucoma has no cure. Treatment is limited to applying medicinal latanoprost drops in order to alleviate the accompanying pressure of the disease, hopefully keeping it from progressing. But drop application can be imprecise, and patients often forget to use them. So two researchers at Massachusetts Eye and Ear Infirmary and Boston Children’s Hospital recently designed a contact lens that delivers medication directly to the eye.
Drug-dispensing contact lenses of the past have been ineffective because they did not dispense the drugs quickly or consistently enough to relieve symptoms. However, the researchers were able to show in a 2014 study that their lens design successfully delivered medication continuously to the eyes of glaucomatous rabbits for one month. In their latest study on glaucomatous monkeys, published in the medical journal Ophthalmology, they were able to show not only that their lens could deliver the drug continuously, but that the lenses alleviated the ocular pressure caused by the disease—possibly even more effectively than manually applied drops do.
“One of the first times I presented our research, I heard some people thought it wouldn’t work in a real contact lens due to prejudices based on previous failures,” Daniel S. Kohane, director of the Laboratory for Biomaterials and Drug Delivery at Boston Children’s Hospital, and a professor of anesthesiology at Harvard Medical School, tells mental_floss.
The secret of their success, says Kohane’s collaborator, Joseph B. Ciolino, an ophthalmologist at Massachusetts Eye and Ear Infirmary, was “the development of polymer drug delivery.”
Kohane explains the process using a Jell-O analogy: Think of the drug as a red powdered dye and the eye as a bathtub. “If you take the red powder and you throw it in a bathtub, all the water in the bathtub becomes red,” he says. However, “if you put the dye into Jell-O, and you throw the Jell-O cubes into the bathtub, the tub will become red very, very slowly.” In the case of the contact lens, “the drug is released slowly by a combination of diffusion and degradation of the polymer film.”
What they found when they applied it to the eyes of monkeys with glaucoma was that “our low-dose lens was equally as effective as the [latanoprost] drops, and in the high-dose lens, was more effective in reducing pressure than the drops,” Ciolino tells mental_floss. “When we first saw the data, we were ecstatic."
Of course, Ciolino is careful not to “overstate” the findings, since they have yet to be proven effective in human trials, but says, “our findings are potentially exciting to those who are interested in sustained drug delivery.” Kohane hopes to start human trials within a year.
For the millions of people with glaucoma, these new lenses may offer new hope for living with the disease.